In recent years, increases to ultrahigh speeds and increases to ultrahigh lifting ranges in elevators are advancing rapidly. In such ultrahigh-speed elevators that have ultrahigh lifting ranges, the diameters and lengths of the ropes that are used is increased, increasing the rope mass ratio in an axle load that acts on a hoisting machine. Some problems in adapting to increases in acting loads have included increasing equipment size and ensuring rope safety factor.
In answer to that, in conventional hybrid ropes, a plurality of steel strands are twisted together around an outer circumference of a high-strength synthetic fiber core. The strength contribution of the fiber portion is increased by the lay pitch of the rope. In addition, a woven fiber sleeve is disposed around the outer circumference of the high-strength synthetic fiber core, such that the sleeve contracts radially when a tensile load acts on the entire rope. Compressive forces thereby arise in the high-strength synthetic fiber core, stabilizing the shape of the rope (see Patent Literature 1, for example).